Learning to read the river can be very frustrating for new prospectors but there is a simple trick that will help you get on the gold. 

Take a metal detector and walk back and forth across the river, when you get a good hit stick some sort of marker on that site, and then follow that signal up and down the river because what you are looking for is a line of black sands, your gold will be in that line. A great deal of the time places I thought would be perfect I found nothing yet friends just a few meters away from me were cleaning up. Once you find the pay streak of black sands you are going to find your gold so it does pay to not only have a metal detector to detect black sands but also teach you how the river is carrying the heavy materials. After you have done this a few times you will look at the current and flow of the river differently.